Receding tide

It's a poignant irony in American history that on Independence Day, 1863, not one but two pivotal battles ended in Union victory, marked the high tide of Confederate military fortune, and ultimately doomed the South's effort at secession. But on July 4, 1863, after six months of siege, Ulysses Grant's Union army finally took Vicksburg and the Confederate west.On the very same day, Robert E. Lee was in Pennsylvania, parrying the threat to Vicksburg with a daring push north to Gettysburg. For two days the battle had raged; on the next, July 4, 1863, Pickett's Charge was thrown back, a…